A Color Controller for a Luminaire

• US 20090231354A1
• Filed: 03/10/2009
• Published: 09/17/2009
• Est. Priority Date: 03/13/2008
• Status: Active Grant

• Current Assignee: Polaris PowerLED Technologies, LLC (Microchip Technology Incorporated)
• Original Assignee: Microsemi Corp. - Analog Mixed Signal Group, Ltd. (Microchip Technology Incorporated)
• Inventors: Aralis, James, Kahn, Simon, Blaut, Roni, Peker, Arkadiy
• Granted Patent: US 8,405,671 B2
• Time in Patent Office: Days
• US Class Current: 345/589
• CPC Class Codes: G09G 2320/041 Temperature compensation
• CPC Class Codes: G09G 2320/064 by time modulation of the brightness of the illumination source
• CPC Class Codes: G09G 2360/145 the light originating from the display screen
• CPC Class Codes: G09G 3/3413 Details of control of colour illumination sources
• CPC Class Codes: H05B 45/22 using optical feedback
• CPC Class Codes: H05B 45/28 using temperature feedback
• CPC Class Codes: H05B 45/325 Pulse-width modulation [PWM]

Abstract

A color controller for a luminaire constituted of: a thru-converter operative to convert an input signal to at least one luminaire drive signal; an illumination sampler arranged to sample an output from the luminaire and generate a representation thereof; and a feedback controller arranged to receive the output representation and generate the updatable conversion factor in cooperation with calibration luminance and color values, wherein the thru-converter operation is responsive to a trigger signal for defining a first and a second mode, the first mode for generating the luminaire drive signal for the luminaire responsive to the input signal being a frame luminance signal and target color signals and wherein the conversion to the at least one luminaire drive signal is responsive to an updatable conversion factor, and the second mode for generating the luminaire drive signal for the luminaire responsive to the feedback controller.

Claims

1. A color controller for a luminaire, the color controller comprising:

a thru-converter operative to convert an input signal to at least one luminaire drive signal;

an illumination sampler arranged to sample an output from the luminaire and generate a representation thereof; and

a feedback controller arranged to receive said output representation and generate an updatable conversion factor in cooperation with calibration luminance and color values,

wherein said thru-converter operation is responsive to a trigger signal for defining a first and a second mode, said first mode for generating said luminaire drive signal for the luminaire responsive to said input signal being a frame luminance signal and target color signals and wherein said conversion to said at least one luminaire drive signal is responsive to an updatable conversion factor, and said second mode for generating said luminaire drive signal for the luminaire responsive to said feedback controller.

2. A color loop controller according to claim 1, further comprising a correction factor calculator responsive to said feedback controller and operative to calculate an updated conversion factor for said thru-converter.

3. A color loop controller according to claim 1, wherein said illumination sampler comprises an RGB color sensor and an integrator.

4. A color loop controller according to claim 1, wherein said illumination sampler comprises an RGB color sensor, an integrator, an analog to digital converter and a color conversion matrix, said analog to digital converter being responsive to the trigger signal.

5. A color loop controller according to claim 1, wherein said second mode is maintained for the illumination period of a full frame.

6. A color loop controller according to claim 1, wherein said second mode is maintained for less than the illumination period of a full frame.

7. A color loop controller according to claim 1, wherein said luminaire drive signal is constituted of a pulse width modulated signal exhibiting a cycle period, wherein a frame exhibits a plurality of pulse width modulated signal cycles, and wherein said second mode is maintained for a single cycle period of said frame.

8. A color loop controller according to claim 7, further comprising a compensation processor in communication with said feedback controller and operative to generate a compensating luminance signal and compensating target color signals for the remaining pulse width modulated signal cycles of said frame, and wherein said thru-converter operation is responsive to the trigger signal for defining a third mode for generating said luminaire drive signal for the luminaire responsive to said compensating luminance signal and compensating target color signals.

9. A color loop controller according to claim 8, wherein said compensating luminance signal and compensating target color signals are determined responsive to the frame luminance signal and target color signals and to the feedback controller.

10. A color loop controller according to claim 7, wherein said feedback controller is arranged to converge over a plurality of single cycle periods of disparate frames.

11. A color loop controller according to claim 7, wherein a trigger generator is arranged to receive a temperature indication of said luminaire, and wherein in the event that said temperature indication is stable over a predetermined time frame, said second mode is maintained for said single cycle period, and in the event that said temperature indication is not stable over said predetermined time frame, said second mode is maintained for the full frame.

12. A color loop controller according to claim 1, wherein said trigger signal is periodic.

13. A color loop controller according to claim 1, wherein said target color signals are frame variable.

14. A color loop controller according to claim 1, further comprising a trigger generator operative to generate said trigger signal.

15. A color loop controller according to claim 14, wherein said feedback controller is responsive to at least one calibration signal, and wherein said trigger generator is operative to:

compare at least one of said received frame luminance signal and said target color signals with said at least one calibration signal; and

generate, in the event that said compared at least one signal is within a predetermined range of said at least one calibration signal, said trigger signal.

16. A color loop controller according to claim 14, wherein said trigger generator is operative to generate said trigger signal responsive to a received signal indicative of a black frame.

17. A method of color control for a luminaire, the method comprising:

converting a frame luminance signal and target color signal, responsive to an updatable conversion factor, to a first luminaire drive signal;

generating, responsive to a trigger signal, a second luminaire drive signal, said second luminaire drive signal being responsive to calibration luminance and color values;

sampling an optical output of the luminaire driven responsive to the second luminaire drive signal;

generating, responsive to said sampled optical output, a revised conversion factor; and

updating said updatable conversion factor with said revised conversion factor.

18. A method according to claim 17, further comprising calculating said revised conversion factor.

19. A method according to claim 17, wherein said sampling comprises integrating an output of a color sensor over a predetermined time period.

20. A method according to claim 17, wherein the luminaire is driven responsive to the second luminaire drive signal for the illumination period of a full frame.

21. A method according to claim 17, wherein the luminaire is driven responsive to the second luminaire drive signal for less than the illumination period of a full frame.

22. A method according to claim 17, wherein said second luminaire drive signal is a pulse width modulated signal exhibiting a duty cycle, and wherein the luminaire is driven responsive to the second luminaire drive signal for only a single cycle period of a frame.

23. A method according to claim 22, further comprising:

generating a third luminance drive signal, said third luminance drive signal responsive to said calibration luminance and color values and to said frame luminance and target color signal; and

driving the luminaire for the balance of the frame with said third luminance drive signal.

24. A method according to claim 22, wherein said generating said revised conversion factor is over a plurality of frames.

25. A method according to claim 22, wherein said generating said revised conversion factor is over a plurality of non-contiguous frames.

26. A method according to claim 22, wherein said trigger signal is responsive to a temperature indication of the luminaire, and wherein the luminaire is driven responsive to the second luminaire drive signal for only a single cycle period of a frame only in the event that the temperature indication is stable over a predetermined time period.

27. A method according to claim 17, wherein the trigger signal is periodic.

28. A method according to claim 17, wherein the target color signal may vary from frame to frame.

29. A method according to claim 28, further comprising:

comparing at least one of said received frame luminance signal and said target color signals with at least one of the calibration luminance and color values; and

generating, in the event that said compared signal is within a predetermined range of said value, the trigger signal.

30. A method according to claim 17, further comprising generating a trigger signal responsive to a received signal indicative of a black frame.